【作者】 刘琳； 陈静；

【Author】 Liu Lin 1 Chen Jing 2(1 Chengdu University of Information Technology,Chengdu 610225)(2 Numerical Weather Prediction Center,Beijing 100081)

【机构】 成都信息工程学院； 中国气象局数值预报中心；

【摘要】 利用新疆地区48个气象台站从1961～2011年的逐日降水观测资料,根据百分位法定义了不同台站的极端降水阈值,又引入了表征降水时间分配特征的新参数—极端降水事件集中度和集中期,重点分析了新疆的极端降水年内非均匀特征。结果表明:1)新疆地区极端降水阈值和年平均极端降水量空间分布基本一致,都以天山地区为最大,呈现北高南低的分布。年平均极端降水频次北部高于南部。2)新疆地区极端降水事件集中度和集中期的空间分布存在一定的差异。总体来说极端降水分布的很密集,各站集中度在0.62-0.9之间,南疆和东疆的集中度大于北疆。新疆地区极端降水主要集中在7月上旬到8月中旬。西南部和天山极端降水出现较早,北疆和东疆极端降水出现较晚。3)近51年来,极端降水事件集中度表现为减弱趋势,而集中期表现为增加趋势,表明极端降水越来越分散,出现时间偏晚。4)极端降水量的季节分配状况和同期的极端降水量存在很好的相关关系。极端降水越分散,集中期越晚,极端降水量越多;极端降水越集中,集中期越早,极端降水量越少。这种相关关系在北疆地区尤为显著。更多还原

【Abstract】 On the basis of daily precipitation data of 48 stations in Xinjiang during 1961-2011,the extreme precipitation threshold value were defined in different stations according to percentile method,variation characteristics of extreme precipitation events(EPE) in Xinjiang were studied.Then,the inner-annual inhomogeneity characteristics of extreme precipitation events were analyzed by introducing the new parameters that reflect the temporal distribution of precipitation : concentration degree(CD) and concentration period(CP).Results reveal that:1) The spatial distribution of the extreme precipitation threshold value is almost same to the annual average extreme precipitation,which shows that the maximum locates in Tianshan mountain area,the value in northern Xinjiang is larger than in the south.The extreme precipitation frequency in northern Xinjiang is higher than in the southern.2)There are some differences in spatial distribution between concentration degree(CD) and concentration period(CP) of extreme precipitation events.The range of the extreme precipitation events concentration degree is 0.62-0.9,which shows that the extreme precipitation appears intensively in Xinjiang.The extreme precipitation events concentration degree in northern Xinjiang is smaller than in the southern and eastern.The extreme precipitation appears mainly between early July and the middle of August.3) The extreme precipitation events concentration degree(CD) shows decrease trends in the last 51 years,however,the increase trends in concentration period(CP).This reveals that: the extreme precipitation appears more and more dispersive.4) The concentration degree(CD) and concentration period(CP) of extreme precipitation events showed a positive correlation with the amounts of extreme precipitation.If the amounts of extreme precipitation were less,the concentration degree(CD) was higher and the concentration period(CP) was earlier especially in northern Xinjiang,vice versa.更多还原